Emplacement age and direction of the Lycian nappes in the Soke-Selcuk region, western Turkey

In the Soke-Selcuk region, western Turkey, the northernmost exposures of the Lycian nappes are found as tectonic slices on the Menderes Massif. The Menderes Massif is represented by a continuous platform sequence and a blocky unit. The lower parts of the Menderes platform sequence is composed of Triassic-Jurassic marbles and an alternation of calcschists and micaschists: however, the upper parts are composed of emery- and rudist-bearing massive marbles. Along a gradational boundary, a blocky unit is found on top of the platform sequence, and it comprises blocks of metaophiolite and emery-bearing marble set in garnet-micaschists matrix. Along a low-angle fault marked by thin slices of red-green phyllites, tectonic slices of the Lycian nappes overlay garnet-micaschists of the massif. The Lycian nappes are represented mainly by a carbonate sequence which consists of dolomites, oncoidal limestones. intraformational limestone conglomerates, and cherty limestones. In the carbonate sequence of the Lycian nappes, undeformed primary structures are clearly observed just several meters above the sole fault, indicating a metamorphic break between the Lycian nappes and the Menderes Massif. The linear fabric in red-green phyllites at the sole of the Lycian nappes trends NNE-SSW, gently plunges to SSW and NNE, and is parallel to the linear fabric of the neotectonic period in the western Turkey. S/C relation suggests top-to-the SSW sense of shear in red-green phyllites. The deformation localized along the sole of the tectonic slices indicates that the red-green phyllites acted as a decollement surface. The deformational features, stratigraphic relations, orientation of linear fabric and metamorphic break reveal that Lycian nappes were emplaced on the Menderes Massif along a low-angle normal fault, after the Early to Middle Eocene Main Menderes metamorphism and prior to the deposition of the Middle Miocene sedimentary cover

Tectonic significance of mafic volcanic rocks in a Mesozoic sequence of the Menderes Massif, West Turkey

The Mesozoic platform sequence of the Menderes Massif consists of thick succession of detrital and carbonate rocks. In this sequence there are mafic metavolcanic rocks at two different levels. The first level of mafic metavolcanic intercalations is in the Late Triassic detrital-rich series located in the Caltasi Formation, which is the lowermost unit of the Mesozoic platform. The second level of the mafic metavolcanic rocks is located in the Late Cretaceous-(?)Paleocene Selcuk Formation laying on top of the platform sequence. The Caltasi Formation, which is composed of mica-schists, thinly-bedded cherts, calc-schist and mafic volcanic intercalations unconformably overlie the Bayindir Formation, which consists of mica-schists, phyllites, and white quartzites of Palaeozoic or probably older age. The mafic volcanic rocks in the Caltasi Formation are alkaline basalts with within plate characteristics and are formed during an intraplate extension. The Caltasi Formation is conformably overlain by the Kayaalti Formation represented by calc-schists, dolomitic marbles, and rudist- and emery-bearing massive marbles in ascending order. The Selcuk Formation overlies the Kayaalti Formation and consists of a mica-schist matrix with allochthonous blocks of mafic volcanic rocks, metaperidotites, metagabbros and massive marbles. The mafic volcanic rocks in the Selcuk Formation are tholeiitic basalts and are petrologically similar to mid-oceanic basalts. The geological and geochemical characteristics of the mafic metavolcanic rocks in the Caltasi Formation indicate that during the Late Triassic, the Menderes platform was segmented, probably by the opening of a branch of the Neotethyan Ocean. Between the Late Triassic and the Late Cretaceous, the Menderes carbonate platform was built up. During the Latest Cretaceous-Early Paleocene, a slab of oceanic crust obducted on this platform and provided slices of mafic metavolcanic rocks into the Selcuk Formation

The problem of the core-cover boundary of the Menderes Massif and an emplacement mechanism for regionally extensive gneissic granites, western Anatolia (Turkey)

In previous studies, the stratigraphy of the Menderes Massif was divided into a Precambrian core and Mesozoic cover associations, the core consisting of gneissic granites and high-grade schists and the cover of mica schists and platform-type marbles. It has also been proposed that the two associations are separated by an unconformity although nowhere is this relation clearly observed

Influence of gold mine on groundwater quality (Efemcukuru, Izmir, Turkey)

Currently, exploration of gold ores is under discussion in Turkey, without considering its adverse affect on the environment. Studying the adverse affect on environment is extremely important because significant civic activities are already taking place on the geological units that contain gold ore bodies in Turkey. Such an area is located at the southeast of Izmir City (Turkey), and approximately 2-km-long gold-bearing ore veins occur close to the Efemcukuru Village. The objective of this study was to describe the characteristics and seasonal variation of the groundwater chemistry and pollution of the aquifer in the ore deposit site, and to determine the impact of ore deposits on groundwater quality. The gold-bearing formation is highly weathered and fractured. The fractures in the geological units control the permeability and the depth of groundwater in the area, The concentrations of Al, Ag, Cu, Cd, Cr, Fe, Pb, Mn, Zn, Ni, and Sb were determined for four well samples and two stream waters for wet and dry seasons. The results showed that the concentrations of most of these elements were below the USA EPA (Environmental Protection Agency) limits; however, Pb and Cd concentrations are slightly above the limits. The results indicate that minerals in gold bodies do not dissolve although the weathering of formations is high. The low concentration of elements in groundwater and streams may be attributed to the high velocity of ground and surface water

Late Cenozoic Geodynamic Evolution of Simav (Kutahya) and Surroundings

The Late Cenozoic geodynamic evolution of Simav (Kutahya) and surroundings was determined by dating active tectonic structures in the region (Simav Fault and Simav Detachment Fault) and granitic and volcanic rocks of the Egrigoz Magmatic Complex. Additionally it was revealed that the currently normal Simav Fault, in previous periods acted as a strike-slip fault according to dating studies of fault planes and field observations. Dating of the fault planes along the Simav Fault determined that initiation of the Simav Fault occurred in the interval between 19.3-26.1 Ma. In this period the Simav Fault demonstrated strike-slip fault behavior in a compressional regime. The results of dating studies of the Egrigoz and Koyunoba Plutons (21.9-26.3 Ma) reveal that the unroofing of these plutons was related to the Simav Detachment Fault (20.0-27.4 Ma). Additionally the presence of volcanism in the time period was identified (7.1-21.3 Ma). The Simav Fault which displayed previous strike-slip character currently has listric normal fault behavior after a tectonic regime change in the Plio-Quaternary. The transition from extensional-compressional regime to a regional extensional regime and cause of the tectonic regime change is thought to be related to the complex subduction process (slab-pull and and roll-back) between the African Plate and Anatolian Plate in the Eastern Mediterranean